Exam 1 Flashcards
What is geology?
Study of Earth’s materials, structures, and processes.
What does physical geology examine?
Earth’s materials and processes.
What is the focus of historical geology?
Earth’s past.
Define physical geography.
Study of Earth’s physical features and climate.
What is the definition of science?
Systematic study of the natural world.
What is the difference between a hypothesis and a theory?
Hypothesis is a testable idea; a theory is well-supported by evidence.
What are natural hazards?
Earth processes (e.g., earthquakes, volcanoes, floods) that pose risks.
What is a setback levee?
A levee built farther from the river to reduce flood risk.
List reasons to study Earth science.
- Understand hazards
- Manage resources
- Mitigate environmental problems
What are the four spheres of Earth?
- Atmosphere (air)
- Hydrosphere (water)
- Geosphere (land)
- Biosphere (life)
What event did the Mt. St. Helens eruption in 1980 demonstrate?
The impact of geological events.
How does human influence affect flooding?
Urbanization, deforestation, levees.
What are drawbacks of levees?
Can worsen downstream flooding, fail under extreme conditions.
What are tectonic plates?
Large, rigid sections of Earth’s lithosphere.
What happens at divergent plate boundaries?
Plates move apart (seafloor spreading, rift valleys).
What occurs at convergent plate boundaries?
Plates collide (subduction zones, mountain formation).
Describe transform plate boundaries.
Plates slide past each other (e.g., San Andreas Fault).
What characterizes a ridge and a trench?
- Ridge: elevated seafloor at divergent boundaries
- Trench: deep depression at subduction zones.
What is seafloor spreading?
New oceanic crust forms at mid-ocean ridges.
Define continental rifting.
Process of continents splitting apart.
What happens during subduction?
Denser plate sinks under another.
How many major tectonic plates are there?
7 major plates.
What is the average rate of plate movement?
~1-10 cm per year.
Where is the youngest rock on the ocean floor found?
Near mid-ocean ridges.
What was Alfred Wegener’s hypothesis?
Continental drift, but lacked a mechanism.
What type of plate boundary is non-volcanic?
Transform boundaries.
Why do mountains formed by continental-continental convergence have no volcanoes?
No subduction occurs; rock layers warp and fold.
Define a mineral.
Naturally occurring, inorganic solid with a crystalline structure.
Differentiate between ambiguous properties and diagnostic properties.
- Ambiguous: Vary between samples (e.g., color)
- Diagnostic: Consistent (e.g., hardness, cleavage).
What is luster in minerals?
How a mineral reflects light (metallic vs. non-metallic).
What does hardness measure in minerals?
Resistance to scratching (Mohs Hardness Scale).
What is streak in mineralogy?
Color of powdered mineral.
Differentiate between cleavage and fracture in minerals.
- Cleavage: breaks along planes of weakness
- Fracture: irregular breakage (e.g., conchoidal fracture).
Why is ice considered a mineral but liquid water is not?
Ice is solid with a crystalline structure; water is liquid.
Why is glass not classified as a mineral?
Lacks an orderly atomic structure.
What is the purpose of the luster test in mineral identification?
Determines if mineral is metallic or non-metallic.
What does the streak test reveal?
Shows true color of mineral powder.
What does the hardness test compare?
Resistance to scratching.
What does the cleavage/fracture test identify?
How minerals break.
What happens to water height during tsunamis near shore?
Water height increases as it slows down.
What caused the 2022 Tonga eruption?
Water-magma interaction caused the explosion.
What did geologists discover on Tofua?
Confirmed indigenous reports of past activity.
